import type { ChatSession } from '@agent-server/chat-ui'
import type { AgentClient } from '@agent-server/client'
import type { FileDto } from '@agent-server/shared'
import { computed, ref, watch, type Ref, type ShallowRef } from 'vue'

/** 本会话的上传与产出文件；收到 file.changed 或上传完成（user.message 带附件）时刷新 */
export function useSessionFiles(client: AgentClient, sessionId: Ref<string | null>, chat: ShallowRef<ChatSession | null>) {
  const files = ref<FileDto[]>([])
  const loading = ref(false)
  let timer: ReturnType<typeof setTimeout> | undefined
  let token = 0

  async function refresh() {
    const id = sessionId.value
    const my = ++token
    if (!id) {
      files.value = []
      return
    }
    loading.value = true
    try {
      const list = await client.sessions.files(id)
      if (my === token) files.value = list
    }
    catch {
      if (my === token) files.value = []
    }
    finally {
      if (my === token) loading.value = false
    }
  }

  function refreshSoon() {
    clearTimeout(timer)
    timer = setTimeout(() => void refresh(), 500)
  }

  watch(sessionId, () => void refresh(), { immediate: true })

  // 文件卡片数量或最新文件事件变化时刷新（含历史加载完成）
  watch(
    () => {
      const items = chat.value?.state.items ?? []
      let sig = ''
      for (const i of items) {
        if (i.kind === 'file') sig += `${i.fileId}:${i.seq};`
        else if (i.kind === 'user' && i.attachments.length) sig += `u${i.seq};`
      }
      return sig
    },
    () => refreshSoon(),
  )

  const uploads = computed(() => sortNewest(files.value.filter(f => f.origin === 'upload')))
  const outputs = computed(() => sortNewest(files.value.filter(f => f.origin === 'agent')))

  return { files, uploads, outputs, loading, refresh }
}

function sortNewest(list: FileDto[]) {
  return [...list].sort((a, b) => Date.parse(b.updatedAt) - Date.parse(a.updatedAt))
}